Method and apparatus for clamping used in molding applications

ABSTRACT

The invention of this patent is a method and apparatus used in molding applications. An external applied force causes an actuator rod to move in a linear motion. In turn, a rotary linkage rotates about its pivot point. This causes a series of linkage connectors to cause linkage arms to rotate around such linkage arms&#39; pivot point. This rotary action causes platens to move simultaneously together to form a clean, even mold. While the platens move linearly on tie bars, which guide such linear movement, the linkage arms and rotary linkage are mounted on a mounting plate. This allows the clamping and applied force stresses on the platens to be dependent on the mounting plate, rather than the tie bars. The platens travel at the same speed and distance in relation to each other. The result is an evenly produced part that comprises two die or mold halves which are perfectly centered.  
     This invention may be employed for injection molding, thermoforming, stretch blow molding, die stamping and the similar devices.

BACKGROUND OF THE INVENTION

[0001] 1) Field of the Invention

[0002] The field of invention relates to a method and apparatus forclamping used in molding applications. More particularly, the inventionprovides for a method and apparatus wherein a platen arrangement meetstogether perfectly, with minimal deflection, to produce an evenly formedpart from the combination of two die or mold halves.

[0003] 2) Description of Prior Art

[0004] The present invention is a method and apparatus for clamping usedin molding applications. It may be used for injection molding,thermoforming, stretch blow molding, die stamping and the like.

[0005] In the prior art, a clamping apparatus for clamping a moldcomprises molding halves disposed on a fixed board and a moving board.Such boards are mounted on tie bars and the moveable parts of theclamping apparatus are also mounted on such tie bars. An example of thisis contained in U.S. Pat. Nos. 5,192,557 and 5,320,517.

[0006] Also, in the prior art, the mechanism which causes the rotationallinear motion of the moveable platen for the mold is mounted on aplurality of tie bars. An example of this is contained in U.S. Pat. No.4,984,980.

[0007] However, the lack of a mounting plate mounting the moving partsof the clamping device causes deflection and an uneven resulting moldedpart.

[0008] In the present invention the primary moving parts are mounted ona mounting plate. This allows for the clamping of the platens andapplied force stresses created thereby to be dependent on the mountingplate rather than the tie bars. In other clamping devices or prior artdevices, the applied force stresses are applied to the tie bars whichcause deflection and an uneven molded part.

SUMMARY OF THE INVENTION

[0009] In view of the foregoing disadvantages inherent in the knownprior art, the present invention provides a method and apparatus used inmolding applications. As such, the general purpose of the presentinvention, which will be described subsequently in greater detail, is toprovide a new and improved device which has all the advantages of theprior art and none of the disadvantages.

[0010] The process begins with an external applied force, traveling in alinear motion, which causes an actuator rod to move in a linear motion.This movement, in turn, causes a rotary linkage to rotate about itspivot point. In turn, a series of linkage connectors, connected tolinkage arms, cause such linkage arms to rotate around such linkagearms' pivot point. This rotary action causes platens to movesimultaneously together to form a clean, even mold. While the platensmove linearly on tie bars, which guide such linear movement, the linkagearms and rotary linkage are mounted on a mounting plate. This allows theclamping and applied force stresses on the platens to be dependent onthe mounting plate, rather than the tie bars.

[0011] The clamping apparatus of the present invention is designed sothat the platens travel at the same speed and distance in relation toeach other. The result is an evenly produced part that comprises two dieor mold halves which are perfectly centered.

[0012] This invention may be employed for injection molding,thermoforming, stretch blow molding, die stamping and similar devices.

[0013] The invention resides not in any one of these features per se,but rather in the particular combination of all of them herein disclosedand claimed, and it is distinguished from the prior art in thisparticular combination of all its structures for the functionsspecified.

[0014] There has thus been outlined, rather broadly, the importantfeatures of the invention in order that the detailed description thereofthat follows may be better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject matter of the claims appended hereto.Those skilled in the art will appreciate that the conception, upon whichthis disclosure is based, may readily be utilized as a basis fordesigning of other structures, methods and systems for carrying out theseveral purposes of the present invention. It is important, therefore,that the claims be regarded as including such equivalent constructionsinsofar as they do not depart from the spirit and scope of the presentinvention.

[0015] Further, the purpose of the foregoing abstract is to enable theU.S. Patent and Trademark Office and the public generally, andespecially the scientists, engineers and practitioners in the art whoare familiar with patent or legal terms or phraseology, to determinequickly from a cursory inspection the nature and essence of thetechnical disclosure of the application. The abstract is neitherintended to define the invention of the application, which is measuredby the claims, nor is it intended to be limiting as to the scope of theinvention in any way.

[0016] It is therefore an object of the present invention to provide anew and improved method and device which has all of the advantages ofthe prior art and none of the disadvantages.

[0017] It is another object of the present invention to provide a newand improved method and device which may easily produce an even andperfectly formed molded part.

[0018] It is a further object of the present invention to promote a newand improved method and device which can produce different size parts.

[0019] It is a further object of the present invention to promote a newand improved method and device which provides a better and more reliableproduct due to the mounting of primary moving parts onto a mountingplate, rather than tie bars so as to counteract vibrations caused whenthe invention is in operation.

[0020] It is a further object of the present invention to promote a newand improved method and device which provides an easy method to set-upand use.

[0021] An even further object of the present invention is to provide anew and improved method and device which is susceptible of a low cost ofmanufacture with regard to both materials and labor, thereby making suchmethod and device economically advantages to use.

[0022] Still yet another object of the present invention is to provide anew and improved device which provides in the apparatuses and methods ofthe prior art some of the advantages thereof, while simultaneouslyovercoming some of the disadvantages normally associated therewith.

[0023] It is a further object of the present invention is to provide anew and improved method and device that can be used employed in a numberof different applications. A few of which are: injection molding, blowmolding, thermoforming and die stamping.

[0024] These together with other objects of the invention, along withthe various features of novelty which characterize the invention, arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and the specific objects attained by its use,reference should be had to accompanying drawings and descriptive matterwhich there is illustrated preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE INVENTION

[0025] The invention will be better understood based on the followingdetailed description. Such description makes reference to the annexeddrawings wherein:

[0026]FIG. 1 shows a top view of the invention.

[0027]FIG. 2 shows a side view of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] With reference now to the drawings, and in particular FIGS. 1 and2, a method and apparatus for the clamping used in molding applicationswhich embodies the principles and concepts of the present invention.

[0029] With reference to FIG. 1, FIG. 1 depicts a top view of thepresent invention. The invention is a method and apparatus for clampingused in molding applications 36 where an external force 30 is applied ina linear motion to an actuator rod 2. The external force 30 can becaused by electrical, mechanical or hydraulic means. The preferredmethod is to use electrical means to apply the thrust load ofapproximately 1200 to 1400 ft./lbs which develops 10 tons of pressure inthe molding area 32. The preferred method is to have the ability toadjust the external force 30 based on the particular moldingapplication.

[0030] Once the external force 30 is applied to the actuator rod 2, theactuator rod 2 moves toward the direction of the molding area 32, andthe actuator rod 2 causes the rotary linkage 4 to rotate around therotary linkage pivot point 6. This rotary motion causes the linkageconnectors 8, which are connected to the rotary linkage 4 to move. Thismovement causes the linkage arms 10 to rotate about the linkage armpivot point 12. The rotary linkage 4 enables both linkage arms 10 totravel at the same speed and distance in relation to each other. Theplatens 18 slide along the tie bars 20.

[0031] A bridge assembly comprises a housing 22, a connector 14, amounting connector 16, a platen 18, a Bellville disc 26 and a bolt 24.There are duel bridge assembly housings 22. The bolt 24 is connected tothe mounting connector arm 16 and the Bellville disc 26 is placedbetween said bolt 24 and mounting connector arm 16. A connector 14 isconnected to said mounting connector arm 16 and the linkage arm 10. Atthe opposite end of the bolt 24 in said bridge assembly housing 22 ismounted a platen 18. The platen 18 is arranged so as to produce a partwith two die or mold halves when meeting in the molding area 32.

[0032] The platens 18 and linkage arms 10 slide along tie bars 20 whichhelp guide the bridge assembly housing 22, with attached platens 18,keeping them moving along a linear motion. The Bellville disc 26 allowfor over stroke compensation. Springs can also be used in place of theBellville discs 26.

[0033] The rotary linkage 4 and linkage arms 10 are mounted on amounting plate 34. This allows the resultant clamping and applied forcestresses to be depended on the mounting plate 34, not the tie bars 20.By this design the force is not applied to the tie bars 20; thus, thereis greater reduction in deflection or an uneven mold since the force, inthe present invention, is absorbed by the mounting plate 34, not the tiebars 20.

[0034] The clamping of the platens 18 occur in the molding area 32produce an even mold as the rotary linkage 4 moves the linkageconnectors 8 about the rotary linkage pivot point 6. So that the linkageconnectors 8 do not continue to move due to this rotary force, thelinkage connectors 8 are stopped by means of a stop block 28. At thispoint, the platens 18 are clamped in the molding area 32 and the clampforce is maintained. No external force 30 is required. To unlock theconnection of the platens 18 and free the molding area 32, the externalforce 30 is applied to move the actuator arm 2 in the opposite directionof its initial movement. The result is an even, perfectly formed ormolded part. The process can then be repeated.

[0035] Tests show that the preferred method is to apply an externalforce 30 such that it is one twentieth to one tenth the actual clampingforce.

[0036] With reference to FIG. 2, FIG. 2 depicts the side view of thepresent invention. A platen 18 is connected to a bridge assembly housing22. The platen 18 is mounted on the tie bars 20. The rod 2 causes therotary linkage 4 and linkage arms 10 to move which causes the platen 18to move. The rotary linkage 4 and linkage arms 10 are mounted on amounting plate 34.

[0037] The invention may be used for injection molding, thermoforming,stretch blow molding, die stamping and the like wherein a platenarrangement is used to product a part with two die or mold halvesmeeting together.

[0038] With respect to the above description then, it is to be realizedthat the optimum dimensional relationships for the invention to includevariations in size, materials, shape, form, function and manner ofoperation, assembly and use, are deemed readily apparent and obvious toone skilled in the art, and all equivalent relationships to thoseskilled in the art, and all equivalent relationships to thoseillustrated in the drawings and described in the specification areintended to be encompassed by the present invention.

[0039] Thus, the foregoing is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and operationshown and described, and accordingly, all suitable modifications andequivalents may be resorted to, falling within the scope of theinvention.

What is claimed as being new and desired to be protected by LettersPatent of the United States is as follows:
 1. A method and apparatus forclamping used in molding applications, comprising: a first platen; asecond platen, opposing said first platen; a tie bar for mounting andguiding said first platen and said second platen; a mounting plate; anda rotary means which causes said first platen to rotate toward and awayfrom said second platen, said rotary means is mounted to said mountingplate.
 2. The device of claim 1, further comprising a first bridgeassembly in which said first platen is mounted on.
 3. The device ofclaim 1, further comprising a second bridge assembly in which saidsecond platen is mounted on.
 4. The device of claim 2 where in s aidfirst bridge assembly, comprises: a first housing; a first mountingconnector within said first housing to mount said first platen; a firstconnector connecting said first mounting connector; a first boltconnecting said first connector; and a first Bellville disc placedbetween said first bolt and said first connector.
 5. The device of claim3 wherein said second bridge assembly, comprises: a second housing; asecond mounting connector within said second housing to mount saidsecond platen; a second connector connecting said second mountingconnector; a second bolt connecting said second connector; and a secondBellville disc placed between said second bolt and said secondconnector.
 6. The device of claim 1, where in said rotary means,comprises: a rotary linkage; linkage connectors connected to said rotarylinkage; linkage arms connected to said linkage connectors; and saidrotary linkage and said linkage arms are mounted on said mounting plate.7. The device of claim 1 wherein, said tie bar is mounted on saidmounting plate.
 8. A method and apparatus for clamping used in moldingapplications, comprising: a first platen; a second platen, opposing saidfirst platen; a tie bar for mounting and guiding said first platen andsaid second platen; a mounting plate; a rotary linkage; linkageconnectors connected to said rotary linkage; linkage arms connected tosaid linkage connectors; and said rotary linkage and said linkage armsare mounted on said mounting plate and said rotary linkage and saidlinkage arms cause said first platen to rotate toward and away from saidsecond platen.
 9. The device of claim 8, further comprising a firstbridge assembly in which said first platen is mounted on.
 10. The deviceof claim 8, further comprising a second bridge assembly in which saidsecond platen is mounted on.
 11. The device of claim 9 wherein saidfirst bridge assembly, comprises: a first housing; a first mountingconnector within said first housing to mount said first platen; a firstconnector connecting said first mounting connector; a first boltconnecting said first connector; and a first Bellville disc placedbetween said first bolt and said first connector.
 12. The device ofclaim 10 wherein said second bridge assembly, comprises: a secondhousing; a second mounting connector within said second housing to mountsaid second platen; a second connector connecting said second mountingconnector; a second bolt connecting said second connector; and a secondBellville disc placed between said second bolt and said secondconnector.
 13. The device of claim 8 wherein, said tie bar is mounted onsaid mounting plate.
 14. A method and apparatus for clamping used inmolding applications, comprising: a first platen; a first bridgeassembly; said first platen is mounted on said first bridge assembly; asecond platen, opposing said first platen; a second bridge assembly;said second platen is mounted on said second bridge assembly; a tie barfor mounting and guiding said first platen and said second platen; amounting plate; said tie bar is mounted on said mounting plate. a rotarylinkage; linkage connectors connected to said rotary linkage; linkagearms connected to said linkage connectors; and said rotary linkage andsaid linkage arms are mounted on said mounting plate and said rotarylinkage and said linkage arms cause said first platen to rotate towardand away from said second platen.
 15. The device of claim 14 whereinsaid first bridge assembly, comprises: a first housing; a first mountingconnector within said first housing to mount said first platen; a firstconnector connecting said first mounting connector; a first boltconnecting said first connector; and a first Bellville disc placedbetween said first bolt and said first connector.
 16. The device ofclaim 14 wherein said second bridge assembly, comprises: a secondhousing; a second mounting connector within said second housing to mountsaid second platen; a second connector connecting said second mountingconnector; a second bolt connecting said second connector; and a secondBellville disc placed between said second bolt and said secondconnector.